Smart cards have become widespread as the uses for such cards multiplies. Subway riders can now purchase a card with a desired value programmed into the card, with the stored value decreasing by an amount equal to the fare each time the user uses the card to gain access to the subway system. Similar cards are used in vending machines, allowing users to carry one card to use for all their vending purchases instead of needing change or single dollars. The programmed amount on the card is reduced each time a purchase is made. Prepaid telephone smart cards are also popular.
Furthermore, smart cards that do not store cash information can also be used. For example, driver's licenses can store personal or medical data, etc.
One disadvantage with smart cards is that the user has no easy way of determining the data that is stored on the card unless he or she remembers it. If the user forgets, then he or she normally must go to a machine that accepts such cards to find out what is stored on the card (e.g., the amount of money that is left on the card).
Portable card readers have been developed to allow a user to more easily determine the remaining value on all the cards in his or her possession. Such a reader, for example, is shown in U.S. Pat. No. 5,015,830 to Masuzawa et al., which features a reader having a slot into which the card is inserted, electronic reading circuits for reading the information stored on the card, and a display for displaying the read information to the user. Although the Masuzawa et al. device is small enough to be portable, it is, nevertheless, too large for many users to carry it around with them on a regular basis. Furthermore, the slot on such a device traps dirt and debris which can eventually render the device inoperative.
To overcome the above-deficiencies, a slotless smart card reader has been proposed in U.S. Pat. No. 5,517,011 to Vandenengel. In this patent, the smart card reader is positioned above and spaced from a smart card. The smart card is a standard smart card that stores information and includes a plurality of contact pads which are used by the reader to access the stored information.
The bottom surface of the reader includes electrical contacts that correspond to the contacts on the smart card, as explained further below. Further, the inside of the reader housing includes a circuit board containing standard circuitry for reading information stored on the smart card via the electrical connection established by the contacts. The reader is typically activated by pressing down on a switch.
To use this reader, the user places the smart card against the reader. Upon activation of the switch, power is delivered to the circuit board from a suitable power source. Information stored on the smart card is read and displayed on a display.
In order to fulfill their desired purpose, smart card readers often will be carried by a user for the entire day. As such, it is desirable that the reader be as small as possible, so that it may easily fit within a user's pocket, wallet or purse, or be attached to a key chain, for instance. However, it is also important that the terminals on the smart card and those on the smart card reader be accurately aligned when using the smart card reader, so that a good electrical connection is made between the smart card reader and the smart card. Conventionally, this has been accomplished by providing the bottom surface of the reader with two perpendicular fixed guides that protrude from the bottom surface at respective edges thereof to guide and position the card when it is placed against the bottom surface of the reader. When the card is properly located, two corresponding perpendicular edges of the card will abut against the respective guides of the reader, so that the contacts of the smart card are positioned in alignment with the contacts of the reader. However, typically the contacts on the card are located in a standardized position, i.e., positioned away from the corner of the card defined by the two perpendicular edges which come in contact with the guides of the reader. As such, in order to properly position the card, the guides of the reader must likewise be placed a corresponding distance from the contacts of the reader. Thus, the size of the conventional reader has been limited by the location of the contacts on the card relative to a corner of the card. Thus, there is a need for a smart card reader which can accurately position the smart card relative to the reader, but which is not restricted in size by the location of the contacts on the smart card.